Matrice 350 RTK

M350/M400/ Matrice 4E are the ways to go in my eyes. Mavic 3E shortly behind them, most affordable but least robust platform.

If the constraint is speed + precision, I don't think photogrammetry is the best way to go. From a distance it looks like a good idea, but don't forget that going from photogrammetry to geospatial data requires a lot of processing, which will take a long time if we're talking about a volume of 20km of road. Furthermore, no, precision is achievable with a good drone like the M3E M4E M350..., but to ensure/justify precision you'll need to set up GCP (i.e. place targets on the ground that you'll survey using GPS) before the flight. So in the end I'm not really convinced that the time saving is there. For trees, yes, it's a problem, but if the roads are of normal width, a drone flying at 10/15m to stay under the canopy will easily be able to take the full-width road. If your markets are large and mainly road-based, consider the option of vehicle-mounted lidar, or vehicle-mounted slam. You'll get speed, live point clouds and precision. But it's expensive.

If most of your projects will be 300 acres or smaller, I would recommend a DJI M300 or DJI M350. If you're getting into 300+ acres, I'd look into Wingtra. Happy Flying.